Humectants, Explained: How They Work In Skin Care + 8 Natural Options To Try

Layering skin care products is a science, and as you become familiar with what works for your own skin, you might hear a ton of science jargon thrown into those conversations.

Such is the case with humectants, emollients, and occlusives: While the monikers may sound incredibly technical, these groups are actually essential for understanding when and how to apply your serums, creams, lotions, et al. Have the chemistry down to a T, and keeping your complexion happily moisturized will be a breeze. 

Humectants pull water into the skin. You might hear "water-loving" or "hydrophilic" tossed around when discussing this ingredient category, and that's because humectants actually bond to water—and this bond allows the ingredients to travel with water as it gets absorbed into the skin cells.

"Humectants are basically 'water magnets,'" says board-certified dermatologist Ava Shamban, M.D., founder of SKINFIVE. "They work to help pull moisture from the air into the upper layer of your skin to keep the skin cells hydrated, plump with a firmness and bounce." They're able to draw in water from the outside air if the humidity is high enough; and because they bond to water, the humectants can also shimmy into the upper layer of your skin and help keep that water in place. 

"Think of the skin as an actual sponge," adds Shamban. "When it is dry, it is thin, brittle, not pliable, rough in texture, dull, and sallow in color. Run it under water, and it is instantly plump, dense, and smooth. Even the color is brighter." The humectants are what help usher that water into the "pores" of the sponge and hold it there, making the appearance plump and full of moisture. 

Essentially, humectants are attracted to water—but this can also backfire, specifically in arid environments. See, when the humidity is high, humectants have an easier time pulling in water from the outside air; but when that humidity dips, the humectants can actually pull water from the deeper layers of the dermis into the stratum corneum (or the outermost layer), which can leave your skin drier than before, as water can easily evaporate on the top layer of the skin. 

"Humectants should be applied to damp skin, not dry skin (unlike antioxidants, which are best applied on dry skin)," says Shamban. With antioxidant serums—like vitamin C, a famous example—you want those active ingredients to penetrate the skin cells. But because humectants are so water-loving, you actually want to give them the water they need to do their job properly. 

Board-certified dermatologist Angelo Landriscina, M.D., seconds the advice: "The humectants in your products, like hyaluronic acid and glycerin, will have an easier time holding on to moisture if you're providing it," he says. Otherwise, those humectants will still do their job—they'll just pull water from your skin instead of the surrounding air, which can leave it even drier than before. 

We'll start with the most well known: Hyaluronic acid is a fabulous hydrator, as it has the ability to hold 1,000 times its own weight in water1. "It gives an immediate improvement in the way the skin looks—less ashy, dry, dull," holistic dermatologist Cybele Fishman, M.D., told us about the beloved ingredient. 

Take a look at your hydrating products, and chances are you'll see glycerin on the ingredient list. This humectant (typically derived from vegetable oils or animal fats) plays very well with other ingredients, helping round out formulas, and it provides hydration and skin protection.

"Along with hydration, glycerin helps with improving the function of the skin barrier, which helps prevent the loss of water, protecting the skin from irritation and improving wound healing in the skin," board-certified dermatologist Raechele Cochran Gathers, M.D., says regarding the ingredient.

"The leaf of the aloe vera plant is rich in water, particularly in the innermost layer, so it helps to hydrate the skin and lock in moisture," explains board-certified dermatologist Marisa Garshick, M.D. "The sugars [it contains], also known as mucopolysaccharides, [also] help to retain moisture in the skin." In fact, when applied topically, aloe vera has been shown to increase the water content2 of the stratum corneum. 

You're probably thinking: Uh, isn't lactic acid an exfoliant? It's true: The AHA is best known for gently sloughing off dead skin cells, but it's also considered a humectant.